Telephone-exchange system



l. L. McQUARRlE AND C. L. GOODRUM. TELEPHONE EXCHANGE SYSTEM. APPLICATION, FILED Aus.1,1919.'

Patented 001 11, 1921.

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UNITED STATES PATENT OFFICE.

JAMES L. MGQUARRIE AND CHARLES L. eoonnmvr, or NEW YORK, N. Y; ASSIGNQRS 'ro WESTERN ELECTRIC COMPANY, INCORPORATED, or NEW YORK, N. Y. A

PORA'IION OF NEW YORK.

TELEPHON E-EXGHAN GE SYSTEM.

Specification of Letters Patent.

Patented Oct. 11, 1921.

Application filed August 7, 1919. Serial No. 315,828. I

Y '0 all whom it may concern:

Be it known that we, JAMES L. MoQUAR- RIE and CHARLES L. GooDRUM, citizens of the United States, both residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Telephone Exchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to improvements in telephone exchange systems and has particular reference to an arrangement for control lin selector switches therefor.

An object of the invention is to control the operation of any one of a plurality of equiv-' alent switches by means common to all of them.

Another object is to provide a number of operating mechanisms, each of which is common to a greater number of switches and automatically pro-allotted so as to be temporarily available to a switch to be controlled thereby.

The inventive idea involved is capable of receiving a variety of expressions one of which, for the purpose of illustrating the invention, is, shown in the accompanying drawing; but it is to be expressly understood that said drawing is employed merely for the purpose of facilitating the description of the invention as a whole and not to define the limits thereof, reference being had to the appended claims for this purpose.

The drawing is a diagrammatic view of the circuit arrangement employed in connection with the invention.

Briefly, the invention consists in providing a pluralitiy of equivalent switches, one

i of which is indicated at S. Each switch is provided with a number of sets of contacts- A and A", etc., and the several sets are associated respectively with operating mechanisms B and B", etc. Each mechanism is common to all of the switches, the same being multiplied thereto through the six conductors shown extending from the meoha nism. The several sets of contacts A, A",

, 1 etc., are preferably arranged in a rotary bank and each is provided with a plunger C such as disclosed in the Keith line switch well known in the art. The operation of this apparatus is the same as in the Keith structure mentioned, and a master mecha- D is provided to control the appara tus whereby all the plungers C will at all a call is initiated and the subscribers line isextended to said switch, the plunger C will be operated, in a manner to later appear, to close the set of contacts A. This operation releases the plunger C from the key shaft which it normally engages, and the closure of the set ofcontacts A operates the magnet of the master mechanism 1) to cause said shaft to be rotated until all the plungers are positioned before the next succeeding idle operating mechanism B, B, etc. In this manner one of the common mechanisms B and B" is pre-alloted for controlling the operation of the particular switch taken for use. In the establishment of a connection, each common mechanism is unavailable for operating some other switch only during the time occupied by the seized switch in extending a calling line. When the seized switch has found an idle trunk, the common mechanism which controlled the operation of said switch, is returned to normal and thus rendered available for another operaall in normal position. The selection of the trunk leading to switch S applies ground to the conductor 2 in any well-known manner and closes a holding circuit for release magnet 3 extending from grounded battery, winding of said magnet and conductor 2 to ground at the line switch or finder. Magnet 3 operates and remains in this condition until the call is terminated. A circuit is now closed for plunger magnet 4 which extends from grounded battery, winding of said magnet,-

baokcontact and left armature of cutoff relay 5, front contact and armature of magnet to gr und: Plunger C s perated by the energization of magnet 4, in the same manner as in the Keith line switch, to transfer the contacts of set A to their alternate posi-' tions. A circuit is then closed for magnet 6 of the master mechanism D extending from grounded battery, winding, armature and back contact of said magnet, side switch wiper 7 in position 1 and contact 8 to ground. This circuit being self interrupting will cause the side switch wiper 7 to step around until a terminal is reached which has no ground connected thereto. The operation of magnet 6 rotates the key shaft can ryin gthe idle plunger C and when a terminal of'the "side switch wiper 7 is reached whlch has no groundapplied thereto, magnet 6 will cease to operate and all the plungers will be positioned before an idle operating mechanism B". In this manner the mechanism B. which is common to all of the sets of contact A" of the several switches will be pre-alloted to control the operation of any switch which may be seized subsequent to the seizure of switch S; When this occurs, ground isapplie'd atone of the sets of contacts A and the master mechanism D 1s again operated to pre -allot another common mechanism.

The closure of the set of contacts A also establishes a circuit for line relay 9 of the mechanism 13, said circuit being traceable from grounded battery, rightwindmg of relay 9, contact 10, subscribers substation apparatus '1, contact '11 and left winding of relay 9 tolground. This relay energizes and closes the circuit for slow-to-release relay 12 extending from grounded battery, winding of said relay, front contact of relay '9 to ground. The switch is now in condltion to receive a series of impulses transmitted from substation 1 by the impulse sending device 13.

The first deenergization of relay 9 in re sponse to the first impulse transmitted closes a circuit for slow-to-release relay 14 extending from grounded battery, winding of said relay, front contact and armature of relay 12, back contact and armature of relay 9 to ground. Relay 14 energizes and, together with relay 12, remains in this condition during the transmission of the series of impulses. circuit for escape magnet 15 of the mechanism B extending from grounded battery, winding ofsaidmagnet, armature and front contact of relay 14 to ground. Escape mag net 15 energizes but at this time has no effect upon the side switch which it controls. Each time relay 9 deenergizesin response to the impulses transmitted to substation 1, a

circuit is closed'for primary ste ping magwinding of "said magnet, contact 17, side switch wiper 18 in o'sition 1,-fro'nt contact. and armature of re; ay 12 and back contact Energization of relay 14 closes a" and armature of relay 9 to ground. Magnet 16 operates to step brushes 19, 20 and 21 of magnet 15 releases, a circuit is again established for the same, which extends from grounded battery, winding of said magnet,

armature and back contact of relay 14, conv tacts 23 and 24, the normally closed secondary, off-normal contact 25 and primary oif-normal contact 26 to ground, the latter contact being closed upon the first step of the switch. Magnet 15 again energizes in thiscircuit but the side switch wipers 18 and 22 remain in position 2 until said magnet deenergizes. When side switchwiper 22 moves from position 1 to position 2, a self-interrupting circuit for the secondary stepping magnet 27 is established which extends from grounded battery, winding, armature and back'contact of magnet 27, contact 28 and side switch wiper 22 to ground. Magnet 27 operates to step the brushes 19, 20 and 21 over the terminals thereof until an idle trunk is found. At the first trunk hunting movement of the brushes of the switch, the secondary olf-normal con tact 25 is opened to break the circuit of escape magnet 15, but this magnet does not release as long as test brush 21 passes over terminals of busy trunks which condition is denoted by ground upon test terminal 29. lmien test brush 21 reaches the terminal of an idle trunk upon which there is no ground, the circuit for escape magnet '15 is broken and said magnet releases to cause the side switch wipers 18 and 22 to move into positioIi 3. f 7

When the side switch wiper 22 moves into position 3, a circuit is established for the cutoff relay 5, extending from grounded battery, winding ofrelay 5, contact 30 and side switch wiper 22 to ground. Relay 5 energizes and locks up through its front contact and right armature to conductor 2. Relay 5 energizinq'opens at its left armature and back contact the circuit for magnet 4 which then releases "and thereby returns the plunger C to'its normal position, whereupon the contacts ofset A are restored. The return to'normal of this setcof contacts opens the energizing circuit of line relay 9 which then releases and retracts its armature which in turn causes the release of relay 12. This relay being slow-to-release does not deenergize until a circuit is established for release magnet 31 of mechanism B, which circuit extends from grounded battery,-winding of magnet 31, side switch wiper 1-8-in position 3, front contact and armature of relay 12 and back contact and armature of relay 9 to ground. Magnet 31 energizes and operates to return the side switch of mechanism B to normal whereupon said mechanism will again be available for the purpose of controlling the operation of some other selector switch through a set of contacts similar to A. The return to normal of the set of contacts A extends the calling line through to the next succeeding switch. After the brushes 19, 20 and 21 have engaged the terminals of an idle trunk, the completion of the establishment of the connection may be controlled through switches similar to that shown in the drawing or through any other means well known in the art.

If the subscriber should abandon the call during the setting of switch S, an energizing circuit will be established for release magnet 31 through side switch wiper 18 in positions 2 or 8 to ground at the back contact and armature of relay 9, and mechanism B" will be returned to normal as previously described. At the termination of a call, the replacing of the receiver upon its switchhook at substation 1, first releases the line switch or finder in a well-known mannerand the release of this switch removes ground from the conductor2. This opens the looking circuit of cutoff relay 5 which then re leases. The holding circuit for release magnet 3 of the switch S is also opened, and said I magnet then deenergizes to restore the switch to normal position, whereupon the same will be available for another operation.

What is claimed is:

1. In a telephone exchange system, a calling line, a plurality of selector switches to which said line may be extended, sets of contacts for each switch, means for pre-alloting one set of contacts to its associated switch, and electromagnetic controllin apparatus .common to a plurality of sets of contacts including the pre-allotted set for controlling the operation of the switch with which said pie-allotted set is associated.

2. In a telephone exchange system, a calling line, a plurality of selector switches to which said line may be extended, sets of contacts for each switch, and electromagnetic controlling apparatus common to certain sets of contacts associated with different switches for controlling the operation of one of said switches.

3. In a telephone exchange system, a calling line, a plurality of selector switches to which said line may be extended, sets of contacts for each switch, electromagnetic controlling apparatus common to certain sets of contacts associated with different switches for controlling the operation of one of said switches, and means actuated thereupon for pre-allotting other sets of contacts and an associated common means.

4. In a telephone system, a calling line, a plurality of trunks, a plurality of electromagnetic controlling equipments therefor each having a set of contacts for each trunk, a plunger for each trunk, means for maintaining the plungers of idle trunks in operative relation to an idle controlling equipment, means actuated by the initiation of a call for seizing an idle trunk, means for actuating the plunger of the seized trunk to connect the same to the preselected controlling equipment, and means thereupon actuated for moving the remaining plungers opaosite the next idle controllin equi ment.

In a telephone exchange system, a calling line, a plurality of selector switches to which saidline may be extended, sets of contacts for each switch, electromagnetic controlling apparatus common to certain sets of contacts associated with different switches for controlling the operation of one of said switches, and means for returning said common means to normal at the termination of the operation of said switch.

6. In a telephone exchange system, a calling line, a plurality of switches, a plurality of means each common to all of said switches for controlling the operation thereof, whereby to extend said calling line, a plurality of sets of contacts associated with each of said common means, means for operating one of said sets when a line is extended to one of said switches to cause the operation of the common means with which said set is associated, means for pre-allotting another common means and its associated sets of contacts for operation when the first mentioned set is actuated, and means for returning said common means to normal at the termination of the operation of said switch, whereby said common means is again rendered available for another operation.

In witness whereof, we hereunto subscribe our names this 4th day of August, A. D.,

JAMES L. MoQUARRIE. CHARLES L. GOODRUM. 

